Nickel germanide with rare earth interlayers for Ge CMOS applications

In this study we show that incorporation of rare earth metal interlayers such as Yb and Er between Ni and n-Ge can simultaneously enhance the stability of the germanide as well as lower the Schottky barrier (φ_b) at the germanide/n-Ge interface. As compared to nickel germanide, thermal stability improvement in the low resistance phase by nearly 150 °C and reduction in the electron Schottky barrier height by 0.13 eV was observed for germanides formed using Yb and Er interlayers. This work addresses key challenges in realizing low resistance contacts to n-Ge for future logic and memory applications.